Hi..there i see your question hasnt been answered as of yet.sorry for the delay..
Ok..If it a thick dense white/grey smoke..coincided with the change in regards XXXXX XXXXX Turbo producing the noise as you describe - its possible this is whats causing your issue..as the turbo does get a feed of oil to keep it cool/lubricated..if one of the seals has gone..this will left oil into the induction system and thus the engine sucks the oil in and hence you get the smoke out the back..certainly check all inside intercooler/intake pipe work/aswell as try and remove the intake tube on the turbo and look inside/till you see the vanes/shaft inside - and see if there is alot of oil in there..then the turbo is likely on its way out.if there is drop in oil then thats what it will be.I do hope this helps.if you need to ask anything else or include anything further then just continue before you rate
its seems to run and not smoke when idle, does that make any difference?
In a sense yes it can as the trubo isnt at it full speed/boost when under throttle..when it spins alot faster - its is really a case of doing these checks above and see whats found..the problem being the turbo can go in two place in itself either on the which your intake.intercooler pipe connects too or the exhaust side which you see your exhaust pipe connected to it too..but like i say above have that checked out as soon as possible as you could risk if there is seal going in that turbo the engine running away on its own oil out of control which means the engine is basically trashed once it eventually stops..I do hope this helps further
Great,just one last question then: on these engines, what turbo should I be looking for, specific or any within the same sort of year range? E61, 3 series, 1 series...they all have pretty much the same engines, presumably the turbos. Can I use any of those if I go for a 2nd hand (I knows its risky, but low on funds)..or do I have to go for exactly the same part number?
Ideally by part number to match.unless you can find the same engine from another series then it will work yes i wouldnt see why not..however ideally in all situations such as turbo problems the best way forward is reconditioned with a warranty/guarantee the most common way of replacement..you could try this site below. www.midlandturbo.com/ .depending where you are in the country maybe try looking up local or near at hand turbo recon companys as they will always usually have recondition turbos which should inc a warranty and would be well worth looking into instead..however as mentioned above before you go ahead with any prucahse best to have the turbo etc checked out..I do hope this helps further